How to Connect PHP Websites to a MySQL Database

In this article, discover how to interact with MySQL database tables using the PHP programming language. PHP is often utilized in conjunction with the open-source MySQL database for web development purposes. Through PHP scripts on a web page, you can directly access MySQL databases. This capability allows you to read from and write to your database straight from your website.

Connect to your MySQL server using the mysqli_connect statement. For example:

$con = mysqli_connect('HOSTNAME','USERNAME','PASSWORD');

If the MySQL database is set up on the same server as PHP, the HOSTNAME will be localhost; if not, it will be the IP address of the MySQL server.

2. Select the database that you want to access using mysqli_select_db. For example:

mysqli_select_db('DATABASENAME', $con)

Where ‘DATABASENAME’ refers to the title of your database. To find out more about the database specifics, refer to the earlier post. How to Manage MySQL Database with phpMyAdmin.

Once the connection has been established and the database chosen, you can proceed to query it using PHP.

To help you create your own connection string, follow the example below.

Example PHP MySQL connection string

This connection string will search a database (your_dbusername), locate a specific table (your_tablename), and then enumerate all values in that table for a designated field (i.e., column) that you specify (your_field).

<?php
	//Sample Database Connection Syntax for PHP and MySQL.
	
	//Connect To Database
	
	$hostname="your_hostname";
	$username="your_dbusername";
	$password="your_dbpassword";
	$dbname="your_dbusername";
	$usertable="your_tablename";
	$yourfield = "your_field";
	
	mysqli_connect($hostname,$username, $password) or 
 die ("<html><script language='JavaScript'>alert('Unable to connect to database! Please try again later.'),
history.go(-1)</script></html>");

	mysqli_select_db($dbname);
	
	# Check If Record Exists
	
	$query = "SELECT * FROM $usertable";
	
	$result = mysqli_query($query);
	
	if($result){
		while($row = mysqli_fetch_array($result)){
			$name = $row["$yourfield"];
			echo "Name: ".$name."<br/>";
		}
	}
?>

MySQL Functions available in PHP language

mysql_affected_rows — Get number of affected rows in previous MySQL operation
mysql_client_encoding — Returns the name of the character set
mysql_close — Close MySQL connection
mysql_connect — Open a connection to a MySQL Server
mysql_create_db — Create a MySQL database
mysql_data_seek — Move internal result pointer
mysql_db_name — Retrieves database name from the call to mysql_list_dbs
mysql_db_query — Selects a database and executes a query on it
mysql_drop_db — Drop (delete) a MySQL database
mysql_errno — Returns the numerical value of the error message from previous MySQL operation
mysql_error — Returns the text of the error message from previous MySQL operation
mysql_escape_string — Escapes a string for use in a mysql_query
mysql_fetch_array — Fetch a result row as an associative array, a numeric array, or both
mysql_fetch_assoc — Fetch a result row as an associative array
mysql_fetch_field — Get column information from a result and return as an object
mysql_fetch_lengths — Get the length of each output in a result
mysql_fetch_object — Fetch a result row as an object
mysql_fetch_row — Get a result row as an enumerated array
mysql_field_flags — Get the flags associated with the specified field in a result
mysql_field_len — Returns the length of the specified field
mysql_field_name — Get the name of the specified field in a result
mysql_field_seek — Set result pointer to a specified field offset
mysql_field_table — Get name of the table the specified field is in
mysql_field_type — Get the type of the specified field in a result
mysql_free_result — Free result memory
mysql_get_client_info — Get MySQL client info
mysql_get_host_info — Get MySQL host info
mysql_get_proto_info — Get MySQL protocol info
mysql_get_server_info — Get MySQL server info
mysql_info — Get information about the most recent query
mysql_insert_id — Get the ID generated in the last query
mysql_list_dbs — List databases available on a MySQL server
mysql_list_fields — List MySQL table fields
mysql_list_processes — List MySQL processes
mysql_list_tables — List tables in a MySQL database
mysql_num_fields — Get number of fields in result
mysql_num_rows — Get number of rows in result
mysql_pconnect — Open a persistent connection to a MySQL server
mysql_ping — Ping a server connection or reconnect if there is no connection
mysql_query — Send a MySQL query
mysql_real_escape_string — Escapes special characters in a string for use in an SQL statement
mysql_result — Get result data
mysql_select_db — Select a MySQL database
mysql_set_charset — Sets the client character set
mysql_stat — Get current system status
mysql_tablename — Get table name of field
mysql_thread_id — Return the current thread ID
mysql_unbuffered_query — Send an SQL query to MySQL without fetching and buffering the result rows